with user windows in kernel mode. We split the windows using %otherwin,
but instead of spilling user window directly to the pcb, we attempt to
spill to user space. If this fails because a stack page is not resident
(or the stack is smashed), the fault handler at tl 2 will detect the
situation and resume at tl 1 again where recovery code can spill to the
pcb. Any windows that have been saved to the pcb will be copied out to
the user stack on return from kernel mode.
Add a first stab at 32 bit window handling. This uses much of the same
recovery code as above because the alignment of the stack pointer is used
to detect 32 bit code. Attempting to spill a 32 bit window to a 64 bit
stack, or vice versa, will cause an alignment fault. The recovery code
then changes the window state to vector to a 32 bit spill/fill handler
and retries the faulting instruction.
Add ktr traces in useful places during trap processing.
Adjust comments to reflect new code and add many more.
Remove the modified tte bit and add a softwrite bit. Mappings are only
writeable if they have been written to, thus in general modify just
duplicates the write bit. The softwrite bit makes it easier to distinguish
mappings which should be writeable but are not yet modified.
Move the exec bit down one, it was being sign extended when used as an
immediate operand.
Use the lock bit to mean tsb page and remove the tsb bit. These are the
only form of locked (tsb) entries we support and we need to conserve bits
where possible.
Implement pmap_copy_page and pmap_is_modified and friends.
Detect mappings that are being being upgraded from read-only to read-write
due to copy-on-write and update the write bit appropriately.
Make trap_mmu_fault do the right thing for protection faults, which is
necessary to implement copy on write correctly. Also handle a bunch
more userland trap types and add ktr traces.
Instead introduce the [M] prefix to existing keywords. e.g.
MSTD is the MP SAFE version of STD. This is prepatory for a
massive Giant lock pushdown. The old MPSAFE keyword made
syscalls.master too messy.
Begin comments MP-Safe procedures with the comment:
/*
* MPSAFE
*/
This comments means that the procedure may be called without
Giant held (The procedure itself may still need to obtain
Giant temporarily to do its thing).
sv_prepsyscall() is now MP SAFE and assumed to be MP SAFE
sv_transtrap() is now MP SAFE and assumed to be MP SAFE
ktrsyscall() and ktrsysret() are now MP SAFE (Giant Pushdown)
trapsignal() is now MP SAFE (Giant Pushdown)
Places which used to do the if (mtx_owned(&Giant)) mtx_unlock(&Giant)
test in syscall[2]() in */*/trap.c now do not. Instead they
explicitly unlock Giant if they previously obtained it, and then
assert that it is no longer held to catch broken system calls.
Rebuild syscall tables.
o Unify <machine/endian.h>'s across all architectures.
o Make bswapXX() functions use a different spelling of u_int16_t and
friends to reduce namespace pollution. The bswapXX() functions
don't actually exist, but we'll probably import these at some
point. Atleast one driver (if_de) depends on bswapXX() for big
endian cases.
o Deprecate byteorder(3) prototypes from <sys/types.h>, these are
now prototyped indirectly in <arpa/inet.h>.
o Deprecate in_addr_t and in_port_t typedefs in <sys/types.h>, these
are now typedef'd in <arpa/inet.h>.
o Change byteorder(3) prototypes to use standards compliant uint32_t
(spelled __uint32_t to reduce namespace pollution).
o Document new preferred headers and standards compliance.
Discussed with: bde
PR: 29946
Reviewed by: bmilekic
during trap handlers.
Implement ptrace_set_pc FWIW.
Initialize the pcb window scratch area in setregs(), and setup user
registers as specified by the SCD.
Submitted by: tmm
kernel from usermode. The remaining user windows are spilled
to the pcb as necessary. The user land window fault handlers
fill directly from the pcb on return.
Add system call entry points.
Submitted by: tmm
